SmpB mutant

Endogenous SsrA tagging activity*^†

EOP^†‡

Apparent K_d, nM^†

SmpB^WT

100

1

1.17 ± 0.018

SmpB¹⁵⁵

149 ± 95

0.131 ± 0.019

ND

SmpB¹⁵⁴

99.4 ± 29

0.291 ± 0.098

ND

SmpB¹⁵³

13.6 ± 12

0.0000556 ± 0.000039

0.848 ± 0.22

SmpB¹⁵¹

1.17 ± 0.43

0.000306 ± 0.0000077

ND

SmpB¹⁴⁸

0.768 ± 0.310

0.000207 ± 0.000044

ND

SmpB¹³⁹

0.469 ± 0.25

0.000234 ± 0.000031

0.519 ± 0.095

SmpB¹³²

0.653 ± 0.455

0.000208 ± 0.000069

ND

SmpB⁵⁹

3.12 ± 4.9

0.0000365 ± 0.000021

ND

SmpB^I154A

116 ± 9.1

0.956 ± -.33

ND

SmpB^I154Q

136 ± 9.7

0.862 ± 0.15

ND

SmpB^I154E

164 ± 81

0.700 ± 0.354

ND

SmpB^M155A

96.6 ± 21

1.03 ± 0.086

ND

SmpB^M155Q

103 ± 38

0.681 ± 0.26

ND

SmpB^M155E

71.3 ± 41

0.700 ± 0.022

ND

SmpB^LI

95.1 ± 4.9

0.881 ± 0.23

ND

SmpB^RK

152 ± 23

0.313 ± 0.047

ND

SmpB^QQ

136 ± 30

0.247 ± 0.182

ND

SmpB^AA

51.9 ± 12

0.631 ± 0.10

ND

SmpB^DE

17.7 ± 8.5

0.0000334 ± 0.000018

0.623 ± 0.13

SmpB^D137R

154 ± 40

ND

ND

SmpB^K138E

135 ± 37

ND

ND

SmpB^R139E

48.6 ± 25

ND

0.411 ± 0.05

SmpB^D137R/R139E

182 ± 64

ND

ND

SmpB^D137A/R139A

178 ± 70

ND

ND

SmpB^K138A/R139A

42.2 ± 3.9

ND

0.877 ± 0.14

SmpB^{D137A/K138A/R139A}

13.1 ± 6.0

ND

0.688 ± 0.07